1. Field
The following description relates to a semiconductor package, and, for example, to a chip on film (COF) type semiconductor package in which a chip is attached on a film.
2. Description of Related Art
To expand the market area of display devices such as liquid crystal displays (LCDs), with promotion of low cost, large scale, and high performance, more pixels have to be integrated in a small area. Thus, as a lead pitch of a driver integrated circuit (IC) which controls each pixel becomes finer within the display device, various packaging methods have been developed.
Packaging methods mainly used in a display device field include a tape carrier packaging (TCP) method, a chip on glass (COG) packaging method, a chip on film (COF) packaging method, and the like. These methods are referred to as wireless methods. To promote reduction in fabrication cost and improvement in yield due to a fine pitch, the share of COF technology in the packaging market has gradually increased since the late 1990s.
The COF technology is a new type of package that has been developed on a display driver IC with the trend of light, thin, short, and miniaturized communication equipment. When a high-resolution display device is implemented using the COF technology, driving frequencies of a television and a monitor are increased from 60 Hz to 120 Hz and, thus, driving load of the driver IC is increased. Thereby, heat generated in the IC is a serious concern.
A method of reducing the heat is disclosed in Korea patent No. 10-0771890.
FIG. 1 is a view illustrating a COF type semiconductor package in the related art. Referring to FIG. 1, in the COF type semiconductor package, a driver IC chip 103, which is a driving chip for display, is attached on a flexible film 101 by an adhesion layer (not shown). A plurality of leads 102 is disposed on the film 101 separately from each other. The plurality of leads 102 is disposed such that internal ends of the leads 102 are concentrated in a central portion.
A driver IC chip 103 is adhered to on upper surfaces of the leads 102 of which portions of the ends are exposed and an underfill layer 107 is filled in surroundings of the leads 102 to which the driver IC chip 103 is attached to stably fix the driver IC chip 103 on the film 101. The reference numeral 106 denotes a bump.
On the other hand, a heat dissipation layer 104 is adhered on a lower surface of the film 101 by an adhesion layer (not shown). The heat dissipation layer 104 functions to transfer heat generated by an operation of the driver IC chip 103 downward through the underfill layer 107 and the lead 102 and to radiate the transferred heat to the outside. The heat dissipation layer 104 may be formed of metals such as aluminum (Al).
In the related art, the heat dissipation layer 104 formed of metals is thickly formed to a thickness of about 200 μm. In particular, when the metal heat dissipation layer is used, a separate insulation tape 105 has to be used. Therefore, it is difficult to reduce a thickness of the semiconductor package. Further, when the metal heat dissipation layer 104 becomes thick, the damage of the semiconductor package, such as lead breakage, occurs.